1. Field of the Invention
The present invention relates to a coating gun wherein a quick-drying paint or bonding agent being discharged therefrom is prevented from leaking out of the gun body and solidifying during a coating operation so that a valve rod will operate smoothly.
2. Description of the Prior Art
A coating gun has heretofore been constructed such that a feed path in the gun body is provided therein with an on-off valve and communicated at the forward end portion thereof with a nozzle at the forward end of the gun body. A guide hole is provided for communicating the feed path and the rear surface of the gun body with each other. A valve rod connected to a valve body of the on-off valve is closely fitted in and slidably extended through the guide hole, and the rear end portion of the valve rod is connected to a driving mechanism for opening or closing the on-off valve, such as an air cylinder or a trigger, which are mounted on the gun body. The valve rod is caused to slide in the guide hole by the driving mechanism to open or close the valve, so that a paint or a bonding agent can be discharged from the nozzle or shut off. In consequence, it is unavoidable that the paint or the bonding agent in the feed path leaks into a gap formed between the sliding valve rod and the guide hole, is conveyed along the outer periphery of the valve rod, and leaks out to the rear surface of the gun body. In the past, when a quick-drying paint or bonding agent such as an emulsion paint has been discharged through the gun, there has been the disadvantage that, during the coating operation, the leaking paint or bonding agent was brought into contact with air, whereby the paint or bonding agent was solidified on the outer peripheral surface of the valve rod between the rear surface of the gun body and the driving mechanism, and the thus solidified paint or bonding agent engaged the rear surface of the gun body or the driving mechanism, so that the valve rod was prevented from operating smoothly.